Typically, portable terminals have a manually operated power-up key to switch on the terminal.
At the beginning of known methods, the key is moved from an idle position in which the terminal is powered off, to an active position in which the terminal is to be powered on. For example, the key is depressed.
If at the end of a predetermined time interval, the key is still in the active position, the terminal automatically starts running a software program.
The predetermined time interval is typically longer than 1 second to avoid that an inadvertent contact on the key definitely triggers the powering up of the portable terminal. For example, inadvertent contact on the key often occurs when transporting the portable terminal.
Delaying an action to be taken after a key is depressed is known from U.S. Pat. No. 3,660,826 to allow bounces that occur when the key is depressed to cease, for example.
On the one hand, it is important to limit such undesirable powering up as much as possible because this consumes energy and reduces the battery autonomy of the portable terminal.
On the other hand, waiting for the predetermined time interval to have elapsed, makes the method of powering up the terminal too long for the user. Indeed, the user has to wait for the predetermined time interval and then for the time necessary to initialize the software program. The user can fully use his portable terminal only when the initialization of the software program has finished.